let arr = ['Traveling', 'Swimming', 'Shopping'];
let [first, second] = arr;  //结构数组

console.log(first);       // Traveling
console.log(second);  // Swimming

//可以跳过
let [,,third, fourth] = arr;  //结构数组
console.log(third);       // Shopping
console.log(fourth);  // undefined

//设置默认值
let [,,third1, fourth1=''] = arr;  //结构数组
console.log(fourth1);  // 空字符串

